Concept Map: Polyuria

A solute diuresis is defined -- urine osmolality >600 mosmol/kg and a total daily osmolar output >1000 mosmol (calculated as the urine osmolality multiplied by the 24-hour urine output).

A water diuresis is defined with a urine osmolality <600 mosmol/kg and often <300 mosmol/kg and a total daily osmolar output <900 mosmol.

Another way to look at it from pure Uosm perspective is U osm <100mOsm/kg is generally a water diuresis from polydipsia or DI.  

Uosm between 100-300 mosm/kg is usually a mixed polyuria( either a central and nephrogenic partial DI and maybe simultaneous water and solute intake and CKD)

U Osm >300 is generally solute diuresis